[project @ 1999-11-02 15:05:38 by simonmar]

This commit adds in the current state of our SMP support.  Notably,
this allows the new way 's' to be built, providing support for running
multiple Haskell threads simultaneously on top of any pthreads
implementation, the idea being to take advantage of commodity SMP
boxes.

Don't expect to get much of a speedup yet; due to the excessive
locking required to synchronise access to mutable heap objects, you'll
see a slowdown in most cases, even on a UP machine.  The best I've
seen is a 1.6-1.7 speedup on an example that did no locking (two
optimised nfibs in parallel).

	- new RTS -N flag specifies how many pthreads to start.

	- new driver -smp flag, tells the driver to use way 's'.

	- new compiler -fsmp option (not for user comsumption)
	  tells the compiler not to generate direct jumps to
	  thunk entry code.

	- largely rewritten scheduler

	- _ccall_GC is now done by handing back a "token" to the
	  RTS before executing the ccall; it should now be possible
	  to execute blocking ccalls in the current thread while
	  allowing the RTS to continue running Haskell threads as
	  normal.

	- you can only call thread-safe C libraries from a way 's'
	  build, of course.

Pthread support is still incomplete, and weird things (including
deadlocks) are likely to happen.

1 files changed, 25 insertions, 4 deletions

diff --git a/ghc/compiler/codeGen/CgTailCall.lhs b/ghc/compiler/codeGen/CgTailCall.lhs
index c33c649d92..46e3b0219f 100644
--- a/ghc/compiler/codeGen/CgTailCall.lhs
+++ b/ghc/compiler/codeGen/CgTailCall.lhs
@@ -1,7 +1,7 @@
 %
 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
 %
-% $Id: CgTailCall.lhs,v 1.22 1999/06/22 08:00:00 simonpj Exp $
+% $Id: CgTailCall.lhs,v 1.23 1999/11/02 15:05:43 simonmar Exp $
 %
 %********************************************************
 %*							*
@@ -39,7 +39,8 @@ import CgRetConv	( dataReturnConvPrim,
 import CgStackery	( mkTaggedStkAmodes, adjustStackHW )
 import CgUsages		( getSpRelOffset, adjustSpAndHp )
 import CgUpdate		( pushSeqFrame )
-import CLabel		( mkUpdInfoLabel, mkRtsPrimOpLabel )
+import CLabel		( mkUpdInfoLabel, mkRtsPrimOpLabel, 
+			  mkBlackHoleInfoTableLabel )
 import ClosureInfo	( nodeMustPointToIt,
 			  getEntryConvention, EntryConvention(..),
 			  LambdaFormInfo
@@ -55,6 +56,7 @@ import Type		( isUnLiftedType )
 import TyCon            ( TyCon )
 import PrimOp		( PrimOp )
 import Util		( zipWithEqual )
+import Unique		( mkPseudoUnique1 )
 import Outputable
 import Panic		( panic, assertPanic )
 \end{code}
@@ -425,6 +427,23 @@ doTailCall arg_amodes arg_regs finish_code arity pending_assts
 
 	(fast_stk_amodes, tagged_stk_amodes) = 
 		splitAt arity stk_arg_amodes
+
+	-- eager blackholing, at the end of the basic block.
+	node_save = CTemp (mkPseudoUnique1 2) DataPtrRep
+	(r1_tmp_asst, bh_asst)
+	 = case sequel of
+#if 0
+	-- no: UpdateCode doesn't tell us that we're in a thunk's entry code.
+	-- we might be in a case continuation later down the line.  Also,
+	-- we might have pushed a return address on the stack, if we're in
+	-- a case scrut, and still be in the thunk's entry code.
+		UpdateCode -> 
+		   (CAssign node_save nodeReg,
+		    CAssign (CVal (CIndex node_save (mkIntCLit 0) PtrRep) 
+				  PtrRep)
+			    (CLbl mkBlackHoleInfoTableLabel DataPtrRep))
+#endif
+		_ -> (AbsCNop, AbsCNop)
     in
 	-- We can omit tags on the arguments passed to the fast entry point, 
 	-- but we have to be careful to fill in the tags on any *extra*
@@ -442,12 +461,14 @@ doTailCall arg_amodes arg_regs finish_code arity pending_assts
 		-- The stack space for the pushed return addess, 
 		-- with any args pushed on top, is recorded in final_sp.
 	
-		-- Do the simultaneous assignments,
-	doSimAssts (mkAbstractCs [pending_assts,
+			-- Do the simultaneous assignments,
+	doSimAssts (mkAbstractCs [r1_tmp_asst,
+				  pending_assts,
 			          reg_arg_assts, 
 				  fast_arg_assts, 
 				  tagged_arg_assts,
 			          tag_assts])	`thenC`
+	absC bh_asst `thenC`
 	
 		-- push a return address if necessary
 		-- (after the assignments above, in case we clobber a live